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The detection of 'virtual' objects using echoes by humans: Spectral cues.
Daniel Rowan1, Timos Papadopoulos2, Lauren Archer3
1Institute of Sound and Vibration Research, University of Southampton, Southampton, Hants, SO17 1BJ, UK.
Hearing Research
|May 17, 2017
Summary
Blind individuals can detect objects using spectral shape changes in echoes, particularly above 3 kHz. Sounds below 3 kHz aid detection but hinder localization, with reverberation impacting results.
Area of Science:
- Auditory perception
- Acoustic echolocation
- Human senses
Background:
- Blind individuals utilize echolocation for spatial awareness and independence.
- The specific acoustic features used in echolocation are not fully understood.
- Spectral shape changes in echoes may be crucial for object detection.
Purpose of the Study:
- To investigate if spectral shape changes in echoes can be used for object detection by inexperienced listeners.
- To identify the acoustic characteristics of echoes important for object detection.
Main Methods:
- Virtual objects were created by convolving noise bands with binaural impulse responses.
- Sounds were manipulated to isolate spectral shape cues.
- Sighted and blind listeners inexperienced in echolocation participated in detection tasks.
Main Results:
- Most listeners could detect hard, flat objects using spectral shape changes.
- Effective spectral changes for detection occurred above 3 kHz.
- Low-frequency sound energy (<3 kHz) was necessary for detection but impaired localization.
Conclusions:
- Spectral shape changes are a viable cue for object detection in echolocation.
- Optimal acoustic features for echolocation depend on the specific task (detection vs. localization).
- Room reverberation can significantly reduce the effectiveness of spectral cues.
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